Base station apparatus, terminal apparatus, and communication method

Abstract

To provide, while achieving coexistence with other radio access systems, a base station apparatus, a terminal apparatus, and a communication method capable of achieving high frequency efficiency. A carrier sense unit configured to secure a channel occupancy time by carrier sense, and a transmission unit configured to transmit at least one subframe in the channel occupancy time are included, and the transmission unit, in a case of communicating with the terminal apparatus only in an unlicensed band, transmits a preamble signal being a common signal in a cell by using an OFDM symbol in an anterior part of a first subframe of the at least one subframe.

1 . A base station apparatus for communicating with a terminal apparatus, the base station apparatus comprising:
 a carrier sense unit configured to secure a channel occupancy time by carrier sense; and   a transmission unit configured to transmit at least one subframe in the channel occupancy time,   wherein the transmission unit, in a case of communicating with the terminal apparatus only in an unlicensed band, transmits a preamble signal being a common signal in a cell by using an OFDM symbol in an anterior part of a first subframe of the at least one subframe.   
     
     
         2 . The base station apparatus according to  claim 1 , wherein the preamble signal includes a cell-specific reference signal and a common downlink control channel. 
     
     
         3 . The base station apparatus according to  claim 1 , wherein the carrier sense unit uses different energy detection threshold values for the carrier sense, between a case of communicating with the terminal apparatus in a licensed band and the unlicensed band, and a case of communicating with the terminal apparatus only in the unlicensed band. 
     
     
         4 . A terminal apparatus for communicating with a base station apparatus, the terminal apparatus comprising:
 a radio reception unit configured to receive multiple subframes from the base station apparatus; and   a demodulation unit configured to demodulate the multiple subframes received,   wherein the radio reception unit, in a case of communicating with the base station apparatus only in an unlicensed band, receives a preamble signal being a common signal in a cell by using an OFDM symbol in an anterior part of a first subframe of the multiple subframes,   the demodulation unit demodulates a data signal from an OFDM symbol other than the preamble signal, and   the preamble signal includes a cell-specific reference signal and a common downlink control channel.   
     
     
         5 . A communication method of a base station apparatus for communicating with a terminal apparatus, the communication method comprising the steps of:
 securing a channel occupancy time by carrier sense; and   transmitting at least one subframe in the channel occupancy time,   wherein the transmitting includes, in a case of communicating with the terminal apparatus only in an unlicensed band, transmitting a preamble signal being a common signal by using a cell in an OFDM symbol in an anterior part of a first subframe of the at least one subframe.   
     
     
         6 . A communication method of a terminal apparatus for communicating with a base station apparatus, the communication method comprising the steps of:
 wirelessly receiving multiple subframes from the base station apparatus; and   demodulating the multiple subframes received,   wherein the wirelessly receiving includes, in a case of communicating with the base station apparatus only in an unlicensed band, receiving a preamble signal being a common signal in a cell by using an OFDM symbol in an anterior part of a first subframe of the multiple subframes,   the demodulating includes demodulating a data signal from an OFDM symbol other than the preamble signal, and   the preamble signal includes a cell-specific reference signal and a common downlink control channel.